A methanisation plant, shut down at the time, was flooded during a period of heavy rainfall. The water level rose to 50 cm on the site. The utility company disconnected the plant’s electrical power supply.

The equipment on the process feed line, located in a 3-m deep pit, was completely submerged. The digestate drying area was also affected. Merchandise intended to be used as a methanisation substrate (downgraded seeds) was flooded, damaging their quality and causing the release of bad odours.

The water arrived through the stormwater drainage network saturated by the overflowing Cosson River, causing the water in the retention basin to rise further. The site had been shut down for more than a year due to a technical incident. Production was supposed to resume 15 days later, but the operator had to postpone the resumption of activity for 2 months. A large quantity of equipment had to be refurbished or replaced (pump motors, PLCs, electrical components, power supply unit, etc.). Each month the plant remained shut down represented a production loss equivalent to turnover of €100,000. As the site is not located in an area identified as floodable, this risk was not taken into account when it was designed (installation of a large amount of equipment at ground level or in a pit). Insofar as possible, the operator plans to upgrade sensitive equipment given operational constraints.